After reading Marcel Riesz, Hestenes discovered the connection of Clifford Algebra with the mathematics of The Special Theory of Relativity and of Quantum Theory, so wrote Space-Time Algebra (1966)

Then, with the Polish mathematician, G. Sobczyk, Hestenes wrote, Clifford Algebra to Geometric Calculus, in which Linear Algebra and Set Theory and Analysis and Differential Forms are derived in Clifford Algebra.

In 1986 appeared a collection of articles by various mathematicians and physicists, Clifford Algebras and Their Applications in Mathematical Physics, Eds. J. S. R. Chisholm and R. K. Common, from a 1985 NATO and SERC Workshop at the University of Canterbury, Kent, England.

In 1985 appeared Hestenes' New Foundations for Classical Mechanics, showing how Rotational Mechanics is facilitated by Clifford Algebra and Planetary Mechanics by Spinors. (Personal note.)

At that time there was promise of an extension, New Foundations of Mathematical Physics, to spell out further what Hestenes first did in Space-Time Algebra, but it has never appeared.